The total length of the river is 2,880 km. It is Pakistan's longest river. The river has a total drainage area exceeding 1,165,000 km2 (450,000 sq mi). Its estimated annual flow stands at around 207 km3 (50 cu mi), making it the twenty-first largest river in the world in terms of annual flow.

The word Indus and the cognate[1] word Sind/Sindhu for the river is ancient. The Ancient Greeks used the word Indós; Hinduš was Old Persian; Sindhu in Sanskrit. Modern languages on the sub-continent use either Sindh (Urdu) or Sindhu (Hindi) or very similar words. There is no doubt that the river gave its name to the country India.[2]

The Indus water system of rivers comprises the main Indus and its major tributaries: the Kabul River and Kurram River on the right bank, and the Jhelum River, Chenab River, Ravi River, Beas River and the Sutlej on the left. The first two join the Indus soon after it leaves the mountains, and the others lower down in the plains. The whole of the Beas and the head reaches of the Ravi and Sutlej are in the Republic of India, while those of the Chenab and Jhelum lie mostly in the disputed Kashmir state.

The entire basin covers an area of about 384,000 square miles of open land, of which 204,000 lie in Pakistan. In addition, there are about 29,000 square miles which lie outside the Indus basin but are dependent on the Indus river system for their water requirements and irrigation supplies.

Without the Indus waters, agriculture in Pakistan would be very uncertain, because there isn't much rain. Even now when Pakistan is being rapidly industrialised, it needs its water resources, because a very big percentage of its existing and proposed industry has to draw upon the agriculture produce for its raw materials. Almost all of the basin in Pakistan receives an overall rainfull of less than 15 inches, 60% of its area receiving less than 10 inches, while, 16% receives less than 5 inches. The rainfull is not evenly distributed throughout the year but is concentrated during the monsoons.

Rising in western Tibet, the Indus runs at first across a high plateau, then the ground falls away and the river, dropping rapidly, gathering momentum and rushing north-west, collects the waters from innumerable glacier-fed streams, and runs north-west between the world's greatest mountain ranges, the Karakoram and the Himalayas. In Kashmir it crosses the United Nations cease-fire line and, in Baltistan District, enters Pakistan-Administered Kashmir. From here on it is Pakistan's river; Pakistan's first town on the upper Indus, Skardu, at 7,500 feet above sea-level, stands on a bluff near the junction of the Indus and one of its great right-bank tributaries, the Shigar. The majority of the people live in Skardu town; others inhabit small and scattered villages along the Indus and Shigar valleys, or tiny hamlets high on the surrounding mountains beside tributary streams or springs.

Walnuts grow along the Indus near Skardu, and poplars and apples; there are delicious melons and nectarines and apricots in the valley of Shigar, but it is difficult to send them "down-country" because they are easily spoilt in transit. Potatoes, maize and other crops need unremitting attention; the patchwork of fields must be fed by small water-channels led off from the upper streams of the Indus, sometimes for hundreds of yards. This means endless, back-breaking work in moving boulders to dam icy water, in continually checking, adjusting and repairing the flimsy clay dykes. Strong winds funnel along the river, and the fine soil blows away and must be replaced. At this height, the growing season is short, and everyman, woman and child is pressed into service. Below Skardu, the Karakorams and Himalayas close in towards the Indus.